Quarterly report pursuant to Section 13 or 15(d)

Summary of Share-Based Compensation Expense (Detail)

v3.7.0.1
Summary of Share-Based Compensation Expense (Detail)
$ / shares in Units, $ in Thousands
1 Months Ended 3 Months Ended
Jan. 31, 2017
tranche
$ / shares
shares
Mar. 31, 2017
USD ($)
shares
Mar. 31, 2016
USD ($)
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Share-based compensation (equity-classified)   $ 846  
Time Vested Restricted Stock Units [Domain]      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant | shares 146,834 254,397  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares $ 51.71    
Share-based Compensation Arrangements By Share-based Payment Award, Award Amortization Period 5 years    
Performance Restricted Stock Units [Domain]      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant | shares   62,675  
Share-based Compensation Arrangements By Share-based Payment Award, Award Amortization Period 5 years    
Share-based Compensation Arrangements By Share-based Payment Award, Number Of Award Tranches | tranche 3    
Share-based Compensation Arrangements By Share-based Payment Award, Performance Period 3 years    
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum   1.49%  
Performance Restricted Stock Units [Domain] | Minimum [Member]      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Shares, Expected to Vest, Percentage 0.00%    
Performance Restricted Stock Units [Domain] | Maximum [Member]      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Shares, Expected to Vest, Percentage 200.00%    
Performance Restricted Stock Units [Domain] | Year 1 [Domain]      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares $ 65.28    
Performance Restricted Stock Units [Domain] | Year 2      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares 61.74    
Performance Restricted Stock Units [Domain] | Year 3      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares $ 61.74    
Employees and Directors [Member]      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant | shares   749,600  
Predecessor [Member]      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Other Stock Based Compensation Expense     $ (602)
Share-based compensation (equity-classified)     (602)
Allocated Share-based Compensation Expense     (609)
Defined Contribution Plan, Cost Recognized     200
Predecessor [Member] | Other Pension Plan, Postretirement or Supplemental Plans [Member]      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Pension and Other Postretirement Benefit Expense     100
Predecessor [Member] | Liability-classified awards      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Share-based compensation (equity-classified)     $ 7
Successor [Member]      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Other Stock Based Compensation Expense   $ 846  
Share-based compensation (equity-classified)   846  
Allocated Share-based Compensation Expense   846  
Defined Contribution Plan, Cost Recognized   100  
Successor [Member] | Other Pension Plan, Postretirement or Supplemental Plans [Member]      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Pension and Other Postretirement Benefit Expense   100  
Successor [Member] | Liability-classified awards      
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]      
Share-based compensation (equity-classified)   $ 0